| 摘要 |
PURPOSE:To obtain a sharp projection image at any time by clamping lug pieces which are divided into an upper and a lower part and projected at the head part of an ocular frame in engagement grooves formed in an attachment from above and below and coupling the device. CONSTITUTION:When the lug piece 18 of the ocular lens frame and the engagement groove 20 of the attachment are coupled with each other, a lug piece 18 is clamped in the engagement groove 20 from above and below to deform elastically and the lug piece 18 is pressed against the upper and lower walls of the engagement groove 20 with the elastic force based on the restoration of said deformation to couple with the engagement groove 20 without any play. Therefore, an ocular 9 moves to the same specific position at any time without any error after the attachment 14 is mounted wherever the ocular lens 9 is before the attachment 14 is mounted. Consequently, when the ocular lens moves to the specific position within a diopter adjustment range by the mounting of the attachment, an invariably sharp projection image is obtained.
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